1. Field of the Invention
The present invention relates to a color toner for non-magnetic mono-component system, and more specifically to the color toner having a narrow charge distribution, good image density, high transfer efficiency, and excellent long-term stability.
2. Description of the Related Art
With digitalization, recent printing techniques are rapidly moving toward full color from black-and-white. In addition, as digital devices are becoming widely used, much research is being devoted to improving image-forming methods and the color toners used to achieve high image quality.
In general, the toner is prepared by using a binder resin, a colorant, a charge control agent, and a releasing agent through the kneading milling method, the suspension polymerization method, the emulsion polymerization method and emulsion aggregation process, etc.
The toner particles are developed with the triboelectrostatic method, and carry a positive or negative charge depending on the polarity of the developed electrostatic latent image. In this process, the composition of components of the toner mother particle, and mainly the additives on the surface of the toner mother particle determine the electrification capability of a toner. Thus, the composition and the method of mixing and adding the additives can be varied to control the electrification capability.
Generally, in the developing process, the additives are used for the purpose of reducing the resistance of the rotating unit which rotates the developing sleeve in the toner supply part, and for preventing the toner from fusing or cohering to the charging blade. Moreover, they can stabilize the triboelectrification characteristic and improve the charge maintenance, and provide a uniform stabilized toner layer formed at low torque and having triboelectrification characteristic in a specific range. However, when the additives are not added uniformly on the toner surface, the charge of toner is not uniform, and a uniform image cannot be formed. In addition, even if the additives are uniformly coated on the toner, adherence between toner and toner, toner and charge blade, or toner and sleeve can happen as printing progresses, in case of toner. In this case, the image grows dim and uneven in the long term. Therefore, to resolve this problem, a design for selecting the proper type, content, and particle size, etc. of the additive is very important.
Particularly, in line with the recent rapid improvement of digital devices, a printer toner to achieve high speed and high quality of color image is required. A toner with a higher and more exact transfer capacity and stable electrification capability in the long term is required.